GST document number changed automatically

Hi,

           For RTV transaction debitmemo invoice generated in payables after return process completed. Then we check the details and validated the invoice, After that GST document number generated as 113 which we defined in document sequence. In india tax details form, we changed the organization and save the record, Then debitmemo invoice status changed as needs revalidation, So we again validated the invoice and check the GST document number in india tax details form. But GST document number changed as 114 which is next number. Please give us the solution on this issue.

Regards,

Sundar